Guard for machine-tools.



T. A? DlCKS.

GUARD FOR MACHINE TGOLS.

"nwucmon FILED JUNE 6. me.

Ext-mated Apn 15, 1919.

- mvam'og Thamxs 14. 0/0/ 6 WITNESSES ATTORNEY WELEIE'SHUBQ', :erur 1'3 frYlZV All FA.

(lne oi the more specific objects of my invention is provide a safety attachment for punch presses and the like in which the secretion of the press depends directly upon the of ion oi the guard, whereoy she ress cannot opera-ice until the guard is in u is or safety position.

' of my invention is to To; y .ltuchment of the char- ,3; zed which the guard, w o moved "so its safety position, is pusvely girevenrsd leaving such. po si bien until the press or other machine tool 1 es operated.

in L accou panymg drawing, Figure l is a side e evamona-i view of e punch press equipped Willi a saiety attachment constru-t ed in. accordance with my present 1nvezition, only so much or the press being shown is necessary to illussrase the safety Fig: 2 is a front elevational View oi. a. portion or lhestructure of Fig. 1, particularly illustrating the mechanism for holding the guard in its safety osition until the press has operated, and ig. 3 is a fragmentary plan View illusirating the construction of a supporting frame which forms part oi my safety attachment;

The press shown in Fig. 1 consists of side frames 1 upon which is supported a' statie cry die and a reciprocating punch 3, the punch being carried by a vertically recip'reea'biiig cross-head 4 which slides-upon guides .5 carried in the machine frame and which is reciprocared. by means of the usual eccentric or crank mechanism 6 carried by a; crank shaft 7 which is adapted to he inbermitcenl; y coupled to the'shafi: of a driv- Whsel-Q The cart-s thus far described of welhknown construction and form no 32ers oi my pl'%(iiili invention. v

Measles sea rus e,

Serial 13o. 3133,5123,

Pivotally supporfcd updii short pins 1O on opposite sides ofthsfl machine, are supporhng castings: ll which carry parallel channel bars 12 which cussed from the from so the rear of the niechine end are counseled across the back; of she machine to form a, rigid frame. As shown, this connection is made by hendin she rear ends of the channel bars 12, as s iown in Fig. 3,

means of a third bar 13; Near their front Specification of Letters Patent. Fggfienfijeqi Apr}, 15;, 1939.,

65 and connecting the bent ends of the bars by ends, the parallel channelloars 12 carry suppores is from which is suspended, by means of upright arms 15, a guard consisling of a, bar 16 adspeed to rest edgewise upon the 'die 2 and a rectangular freme 17 covered wholly, or in. part, with wire netting 18/ The supports 1-1 are slidable along the bars 12, and the arms 15 are also slidably secured in the supports 14, the position of each of the supports 1% bein fixed by means of a tllllIHb-SCFEW 19 Whicl also serves to fir; the position of the arm' 15 with respect to the support 14:. r v

The frame formed by the parallel channel bars 12, guard bars 15 and 16is reciprccated around the pivot pins 10 by means of a treadle 20 pivoted to the frame of the machine at- 21' and normally drawn upward by means of e. spring 22. The treadle is connected, by means of a link 23, to clever 24 pivoted at 25 and attached, at its free end, to the lower end of a link 26 which is pivotarlly secured to a pin 27 carried by a cam plate 28 that is loosely mounted upon a pin 29 secured to the-machine frame.

by the pivoted support 11.- 'A press-operating link 32 is operatively connected, at its upper end, to a bell-crank lever 40 which is adapted to actuate a clutch 41 through which motion is imparted t the crankshaft 7, and which is normally pressed upwardly by meansof a spring 42. At its lower end, the link 32 carries a slotted member 33 which surrounds the pin 27 and thereby establishes a lost-motion connection between the link 32 and the link 26. The linkage 'mechanism just described is so arranged that,

when the treadle 20 is depressed, the cam.

plate 28 is rotetediu a counter-clockwise diroot-ion around the pivot pin 29 and, by reason of the engagement between the cam surface 30 and the roller 31, rocks the guarddid the connecting hm 13 and the D The cam plate 28 is provided with a curved'surface 30 whichengages a roller 31 that is rotatablycarriedflflfi carrying frame around the ivot pins 10 from the position shown in full lines in Fig. l, to the position shown in dotted lines, in which latter position the bar 16 of the guard rests upon the die plate 2. When the; guard has reached the latter position, thc pin 27 "is brought to the lower end of the SlOlIydl'L the member 83 and pulls the link 32 down- Ward, thus actuating the clutch mechanism to operate the press. If, however, the bar 16 of the press, in its downward movement, encounters the hand of the operator or any other obstruction, the pin 27 will not be lowered far enough to exert a pull upon the link 32, and the press will therefore not be operated until such obstruction is removed from beneath the guard. When the treadlc is released, the guard is returned to its upper position by means of a spring by means of a suitable counterweight at the rear of the guard frame.

The structure described above is snflicient for the proper operation of the guard while the press is normally running. There is a possibility, however, that, when the press is idle, the treadle may be depressed and the cycle of operations described above may he performed without, however, actuating the Dress. Under these circumstances, he clutch "-w llremain connected unt l power is applied to the press, but the guard; will be allowed to return to its raised or inoperative position,and, When the press is first started, the punch 3' will make one reciprocation without being protected by the guard. In order to prevent such an occurrence, I provide a latch which holds the guard in its downward or operative position until the press, has made a working stroke, This latch is best shown in Fig. 2 of the drawingand consists of a fiat, annular member 35 loosely pivoted 'at36 to the machine frame and provided, at its lower land, with a notch 37 which is'adapted to engage the upper and inner angle of the adjacent channel bar 12 when the bar is in its lower-position. The weight of the latch member 35 is so distributed around the pivot that the member tends to assume its latching position shown in full lines in Fig, 2. Secured to the cross-head fl adjacent to the upper curved end of the latch 35 1s a slotted plate 38 which adjustably secured to the icy means of bolts 39.

in the operation of the latching mecha nism described above, the parts are in the positions shown in full lines in Fig. 2 at the beginning of each stroke oit'the machine.

nuances W hen the frame which carries the guard moves downward, it deflects the latch 35 to the left, and, as'soon as the frame has passed below the latch, the latch will immediately swing back far enough to bring the notch 37 into holding engagement with the adjacent bar 12, and this relation will be maintained until the cross-head 4' descends and brings the member 88 into sliding engagement with the upper curved end of the member 35, thereby rotating the latch again around its pivot and releasing the bar 12 which permitslthe frame to rise to its inoperative position. i

It will he observed that the safetydevice which I have shown and described is so related to the operating parts of the press as to effectually protect the operator from injuryand that it is substantially impossible for the press to operate except when the space around the punch and the die is unoh-. struct'ed, It will also ".be understood that this device is capable of numerous structural modifications While retaining the essential features of my invention, and 1 therefore desire thatno limitations shall be imposed upon my invention except such as are indi cated in the appended claims.

I claim as my invention:

1, A safety attachmentforpunch presses and similar machine tools comprising a pivoted supporting arm, a guard carried there by, a lever mechanism for bringing the guard into operative position and for there after operating the press, a latch normally tending to swing into the path ofreovement of the said arm, and means associated with a moving part of the machine for deflecting the said latch from the path or" the said arm.

predetermined intervals'to swing the said lat-ch and release the said arm,

in. testimony whereof, if here hereunto subscribed my name this 31st dayor May, H 1916, I

THOMAS A. DICK? 

